Friday, May 30, 2014

According to researchers from Massachusetts General Hospital (MGH), activating a particular region of the brain affects the decision-making progress. The team was able to change monkeys' choices between two images by artificially stimulating the ventral tegmental area (VTA), which consists of a group of neurons located at the base of the midbrain.

"Previous studies had correlated increased activity in the primate VTA with positive events experienced by the animal but could not prove that VTA activity actually caused behavioral changes," stated study author, Wim Vanduffel, PhD, of the Martinos Center for Biomedical Imaging at MGH and head of the Laboratory for Neuro- and Psychophysiology at the University of Leuven. "Studies in rodents have shown that artificially manipulating VTA activity strongly influences behavior, and our work has bridged the gap between rodent and primate."

In this study, the team placed microelectrodes in the VTAs of macaque monkeys using high-resolution magnetic resonance imaging as a guide. In the beginning of the experiment, the monkeys were showed two images. The researchers recorded which image the monkeys preferred by observing their eye movements. The monkeys had been trained to look initially at a white square and then at either picture. The picture that the monkeys looked at most frequently was considered the favored one.

After knowing which image the monkeys preferred, the researchers showed the monkeys the picture pairs once again. This time when the monkeys looked at the less favored picture, the team administered mild stimulation to the VTA. The researchers noted that the stimulation caused the monkeys to change their preference. The stimulation was then applied when the monkeys glanced at their preferred image. The monkeys' preference changed back to normal.

Researchers at the University of Louisiana at Lafayette's New Iberia Research Center have conducted a vaccine trial on chimpanzees that could help protect endangered wild apes from deadly infectious diseases, such as the Ebola virus.

It's believed to be the first time that a vaccine intended for apes – rather than humans – has been tested on captive chimpanzees. Results of the trial are published in the latest issue of Proceedings of the National Academy of Sciences.

Vaccines haven't been used to fight outbreaks of diseases in chimpanzees and gorillas because of concerns about their safety, according to the journal article.

But Joe Simmons, NIRC director, said high mortality rates have made many conservationists more receptive to the potential protection of vaccines.

"Preserving endangered chimpanzee and gorilla species is a common cause for conservationists and medical researchers," he said.

NIRC researchers tested a virus-like particle vaccine, which contains a small amount of viral proteins but is incapable of replicating. "The vaccine doesn't cause infection, but it does cause an immune response to those proteins that can protect against infection," Simmons explained.

Six monkeys died of unknown causes while in quarantine at the Oregon Zoo.

The cotton-top tamarins, a species of small New World monkey, were part of a group of nine that arrived at the zoo on May 22.

"It's sad," said zoo visitor Maria Maarigal. "The Oregon Zoo should have taken care of them properly, how can this happen?"

The remaining three monkeys, including a 5-week-old baby, appear to be in good health, according to zoo workers. They are still being closely monitored.

The deaths were discovered by a veterinary staff member early Sunday morning. Initial necropsy results were inconclusive, according to a zoo statement.

"We are shocked and heartbroken," said zoo veterinarian Dr. Tim Storms. "We are really trying to get to the bottom of it. Certainly, I have seen animals die in unfortunate situations before, but never six animals all at once like that."
Tissue samples were submitted to a pathologist for further analysis. Zoo officials hope to receive those results within a few weeks.

"At this point it could be anything, from exposure to something to disease or even acclimation problems, we really don't know," said Storms.

Friday, May 16, 2014

A gorilla at the Knoxville Zoo is up and about, just one day after he had surgery to repair a broken leg.

Wanto, a 37 year old silverback gorilla, broke his right femur in what zoo officials called a "freak accident" on Monday, while climbing bars in the indoor courtyard of his exhibit. His keepers think he may have been trying to avoid the three female gorillas in his group who like to tease him.

The surgery was a little risky, since he's considered an "old man" in gorilla years and has an existing heart condition, but zoo officials wanted to give him the best chance to get better.

Researchers have shown for the first time that it is possible to grow new bone from stem cells made from an animal's own skin cells. While this is not the first successful stem cell therapy tested on animals closely related to humans, it offers another potential source of stem cells for transplantation—the individual’s own adult cells.

In the new study, published online today in Cell Reports, researchers chose a type of monkey called the rhesus macaque as a model for how the technique might work in people. These primates are physiologically similar to humans, especially when it comes to their immune system and how it reacts to foreign bodies.

Researchers harvested skin cells from the monkeys and then genetically reprogrammed them into the equivalent of embryonic stem cells. Unlike adult cells, which are committed to being a specific type of cell (such as skin, bone, or heart-tissue cells), these so-called induced pluripotent stem cells (iPSCs) have the ability to mature into any other type of cell.

Scientists have successfully repaired damaged monkey hearts by injecting new heart cells made from human stem cells, paving the way for a trial in humans before the end of the decade.

Researchers now hope that the treatment could give patients a new lease of life after massive heart attacks that cause scarring and ultimately heart failure.

"When human embryonic stem cells were first discovered, this is just the sort of therapy people hoped they would lead to. We are optimistic, but we are also cautious," said Charles Murry, who led the team at the University of Washington in Seattle.

The heart is one of the poorest organs in the body at repairing itself when it sustains damage. After a heart attack, muscle tissue in the heart dies off, and is replaced a month or so later with scar tissue. This does not contract like normal heart tissue, so the heart is weakened and struggles to pump blood around the body.